/Engine/Source/Editor/UnrealEd/Public/UnrealEdMisc.h
Called from tab manager when the tab changes
void OnActiveTabChanged ( [TSharedPtr](API\Runtime\Core\Templates\TSharedPtr)< [SDockTab](API\Runtime\Slate\Widgets\Docking\SDockTab) > PreviouslyActive, [TSharedPtr](API\Runtime\Core\Templates\TSharedPtr)< [SDockTab](API\Runtime\Slate\Widgets\Docking\SDockTab) > NewlyActivated )